Where trees are no longer trees they are rocks and crystals.
The Petrified Forest National Park is known for its fossils, especially of fallen trees that lived in the Late Triassic period of the Mesozoic era, about 225 million years ago. Most of the logs in the Petrified Forest retained their original external form during petrification but lose their internal structure. However, a small fraction of the logs and most of the park’s petrified animal bones have cells and other spaces that are mineral-filled but still retain much of their original organic structure. [wikipedia]
The Painted Desert is the colorful Chinle, which appears on the surface in many parts of the southwestern United States and from which the Painted Desert gets its name, is up to 800 feet thick in the park. It consists of a variety of sedimentary rocks including beds of soft, fine-grained mudstone, siltstone, and claystone—much of which is bentonite—as well as harder sandstone and conglomerate, and limestone. Exposed to wind and water, the Chinle usually erodes differentially into badlands made up of cliffs, gullies, mesas, buttes, and rounded hills. Its bentonite clay, which swells when wet and shrinks while drying, causes surface movement and cracking that discourages plant growth. Lack of plant cover makes the Chinle especially susceptible to weathering. [wikipedia]